Genome-Wide Identification of Histone Modification (HM) Gene Family and Their Expression Patterns Under Abiotic Stress and Different Developmental Stages of Tea (Camellia assamica)

Histone modifications (HMs) play important roles in the regulation of gene expression in every domain of life. Tea (Camellia assamica), which is a woody perennial plant, is exposed to various stresses during its different developmental stages and HMs are expected to play crucial roles in its adaptation under different stress conditions. Characterization of tea HM genes is still unexplored, therefore in the present study a complete genome-wide characterization of HM genes was performed. Around 77 HM genes representing 10 subfamilies were identified. Further, detailed characterization of gene structures, identification of conserved motifs, and domains, phylogenetic analysis, identification of cis elements and localization in the chromosomes were carried out. Comparative analysis showed that C. assamica had nearly half of the HM genes (77) that were found in China type tea, i.e., C. sinensis (151). Protein-protein interactions showed that HM genes of C. assamica participated in different plant developmental processes, seed dormancy, phytohormone signaling and biotic as well as abiotic stresses. Gene expression analysis through qRT-PCR from five different developmental tissues of tea plant and under three different abiotic stresses (cold, dehydration and salinity) showed that 26 family members had differential expression indicating their involvement in various developmental stages or responses under different abiotic stresses in tea plant.